Yeah, the water goes to your blood and too much water will thin out your blood so it can't carry oxygen and you'll die of asphyxiation and drowning kind of.
Yes! It's possible! I don't know how many years ago it was or what, but there was a lady who died because of it and it was in the news and I remember my mom telling me that "too much of anything can kill you". It's kind of weird, I can remember that she drank too much water because she was trying to win some contest...
I think it must be possible... (prepare for bio nerd explosion) because if there was a crapload of water in your body, and the normal amount in your cells, the water would use osmosis to diffuse to the hypertonic solution because the concentration of water there is lesser... then your cells would explode from the pressure of the water against the cell membrane... but that's be a HUGE amount of water lol